Sound-reproducing unit



Jan. 10, 1928.

P. G. ANDRES SOUND REPRODUCING UNIT Filed Dec. 18, 1926 Patented Jan.10, 1928.

UNITED STATES} PATENT OFFICE.

PAUL G. ANDRES, OF ST. CHARLES, ILLINOIS, ASSIGNOR T NEWCOMBE-EAWLEY,INC., 01 ST. CHARLES, ILLINOIS, A CORPORATION 01 ILLINOIS.

sounn-nnraonucme UNIT.

Application filed December 18, 1928. Serial No. 155,600. E

The present invention relates to sound reproducin or regeneratingdevices, such as those used in radio-telephonic reception.

Among the objects of the invention is to provide a novel device,preferably as a unita means, for rendering sounds efficiently an withsubstantiall uniform amplitudes throughout the audi le voice and musicrange of frequencies.

Another object of the invention is to provide sucha device with soundproducers or sound emitting members, regenerating units havingdifl'erent natural periodicities such that it may be high in the case ofthe low frequency responsive unit, and be lowin the caseof the highfrequency responsive unit, thereby avoidin marked resonance effects in.the output of the device. To arrive at such results, theillustrativeembodiment is disclosed with electrical inductances or coilsarranged in a filter circuit with one coil responding best to the lowfrequencies by reason of the high impedance of theinductance, and withanother coil responding best .to high frequencies by reason of the low1mpedance thereof. Each coil is designed to actuate a producer andpreferably is connected in series with the other coil or coils, suchthat the inductive reactances may be in inverse ratio to the fundamentalfrequencies of the sound producers or units.

The invention also may comprehend the shunting of a capacity, such as acondenser, between the reactances or as a by-pass for the high frequencyaudio current for one or more of the coils, such that the high capacityreactance ofthe condenser at low frequencies may compel the lowfrequencies to pass through the other coil or coils, or the coil unitresponsive to low frequency current. In this way the response of eachunit may be matched to the total response desired to obtain a uniformresponse at all audible frequencies, the units interacting electricallysound producers, as to render the uniformity of final rendition andamplitude, thereof, such device also preferably including between thereactances, a capacity shunt for by-passing the high frequencies.

Other. objects, features of the invention, capabilities and advantagesare comprehended by the invention as will later appear and areinherently possessed thereby.

Referring to the drawing, Fig. 1 is a transverse sectional view throughan illustrative embodiment of the invention with certain parts broken orshown in fragments.

Fig. 2 is a schematic diagram of the power unit.

Fig. 3 is a view showing an alternate mode of connecting circuits.

And, Fig. 4 is a diagrammatic view of the circuits that may be used.

Referring now more in details to the drawings, the embodiment selectedto illustrate the invention is shown as comprismg an electro-magneticregenerating system having a permanent magnet 1 to the poles 2 and 3 ofwhich are secured polar members or shoes 4 and 5 cooperating with coilsor solenoids 6 and 7, an interpolar member 8 being also located betweenthe coils.

lVithin the coils 6 and 7 are fulcrumed armatures 9 and 10 with thearmature 9 connected at one end thereof to an actuating member orelement 11 connected to a vibratable diaphragm 12 of a loud speaker horn13 as clearly shown in Fig. 1 of the drawings. The outer end of theother armature is connected with an actuating element 14 connected tothe end of a vibratable elementin the form of a reed 15 connected at itsother end to the permanent magnet as indicated at 16 in Fig. 1 of thedrawings. The reed 15 has a natural periodicity and at one of its looppoints, such as the point 17, is connected an actuating element 18secured at its outer end to the apex of a cone 20 as clearly shown inthe drawings.

. The cone is of the free edge type being connected at one or morepoints by a fiexible connector 21 to bosses 22 provided on the innersurface of a rim portion 23 of an end casing member 24, the latter beingsuitably provided with means for supporting the same upon a support asdesired. The

member 24 has a side wall 25 to which may be secured a base member 26 ofthe horn, the latter having a threaded portion 27 secured to a threadedpart of the member 26, and provided with suitable grooves with rings 28for supporting and clamping the margins of the diaphragm 12 as clearlyshown in the drawings.

The coils are connected electricall in series through conductors 30 and31, inding posts '32 and 33 suitably carried by the permanent magnet,and proceedin by leads 34 and 35 to the coils 6 and 7 and aninterconnecting lead 36 as clearly shown in Figs. 2-and 3 of thedrawings. Where the coils are of such value that it is desired that highfrequencies will freely pass through one of the coils, such as the coil7, a condenser 37 may be connected in shunt with the coil 6 so as toprovide a path for the high frequencies without the effect of the samebeing impressed upon or felt as electromotive ener in the coil 6, yetthe condenser bein 0 such a capacity that freuencies 0 low value willfreely pass t rough the coil 6 to produce its elfect upon the dlaphragm12. If the values of the coils be reversed depending upon theperiodicities of the diaphragms 12 and 20, the condenser 37 may beplaced in shunt with the coil 7, as clearly shown in Fig. 3, instead ofin shunt with the coil 6 as shown in Fig.

' claim 2 of the drawings. In this arrangement of the circuit the highfrequencies will pass freely through the coil 6 and condenser 37 whilethe low frequencies will find a free path through the coil 7.

The diagram in Fig. 4 is to dia rammatically show the circuit in simplied form and the coils are alternately representative of coils 6 or 7 and7 or 6 dependin in which way the condenser is connected in shunt withrespect to either one of the coils.

While I have herein described and upon the drawings shown anillustrative embodiment of the invention, it is to be understood that itmay comprehend other forms constructions, arrangements of parts anddetails without departin from the spiritthereof.

Having thus isclosed the invention, I

varyin tances having reactances in inverse ratio to the fundamentalfrequencies of the producers affected thereby, and capacity shunt meansfor by-passing high fre uencies about the inductance high in impe anceto said high frequencies.

3. A sound regenerating device, comprismg sound producers of differentnatural periods, means for actuating said producers and comprising anelectro-magnetie device for each sound producer, said electro-magneticdevices having reluctances varying inversely with said natural periodsof said producers.

4. A sound regenerating device, compris- 1ng sound producers ofdifferent natural periods, means for actuating said producers andcomprisin an electro-magnetic device for each soun producer, saidelectro-magnetic devices having reluctances varying inversely with saidnatural periods of said producers, and a capacity shunt for one of saidelectro-magnetic devices.

5. A sound producing device, comprising sound emitting members havingdifi'erent resonance points and a unitary electroma etic meanscomprising serially connected inductances for affecting said members,the reactances of said inductances var ing inversely with resonances ofsaid mem ers.

6. A sound producing device, com rising sound emitting members havingdifferent resonance points and a unitary electromagneticmeans comprisingserially connected' mductances for affecting said members, thereactances of said inductances var ing inversely with resonances of saidmem rs, and a capacity shunt for one of said inductances.

7.. A sound regenerating device, comprising sound emitting diaphragmaticmembers;

an amplif ing means for one of said members, an e ectro-magnetlc devicefor actuating said members and comprising an inductance for each of saidmembers and electrically connected serially, said inductances varyinwith the resonance characteristics of sai members.

8. A sound regenerating device, com ris ing sound emittingdiaphragmaticmem rs, an amplif ing means for one of said members, an e ectro-magneticdevice for actuating said members and comprising an inductance for eachof said members and electrically connected serially, said inductanceswith the resonance characteristics of sai members, and a capacity shuntfor one of said inductanees.

In witness whereof, I hereunto subscribe my name to this specification.

PAUL G. ANDRES.

